Humans (Homo sapiens) are the only known naturally sapient species of biological life. A ninety-nine-billion-strong branch of Earth’s great apes, they are kaleidoscopically diverse, and every sapien alive today either is one, is descended from one, or has an ancestor that was brought to self-awareness by one.¹

Humans originated around two hundred thousand years ago on the plains of Eastafrica. They have a knack for pattern recognition, a tendency to cluster into social groups absent any prodding, and are adept makers and users of tools. These attributes have allowed them to progress at an exponential rate as they spread across the Earth, the planets, and eventually the stars: whereas hundreds of millennia passed between the taming of fire and the tilling of soil, it took less than a hundred years for them to go from inventing the flying machine to living in outer space.

Biology

It is difficult to speak about humans in biological generalities, since they frequently and actively modify themselves to suit the needs of their habitats, to make themselves stronger, or for pure æsthetic appeal. Nevertheless: generally, humans are bipedal (but space-adapted ones see little distinction between two or four feet). They stand on average just under two metres in height (but women are usually shorter, Martians often breach that mark, and dwarfism predates any kind of gen­gi­neer­ing by centuries). They have only a thin coat of hair on their bodies below their head (but animalistic tweaks have been popular æsthetic changes since the beginning), and underneath their skin ranges from a pale eggshell colour to a dark mahogany (but some spacers are an obsidian black to protect from radiation, and Saturnians like to hark back to old Earthling ideas of aliens with vibrant greens and blues).

Humans are the best long-distance runners in the animal kingdom, have accurate hand–eye coördination, and boast a powerful heart compared to other primates.² They are omnivorous (but taboos against eating meat are common), thrive at temperatures of around 20 degrees Celsius, give or take a couple dozen (but that’s why they invented clothes, and most Earthlings and Martians would keel over in the sweltering jungles of Venus), but require a steady supply of oxygen to breathe (which merfolk can obtain by filtering water in gills around their neck, and which space-adapted humans can save in reserve for up to three days). Without medical intervention a baseline human can live for between 80 and 120 years; with the advent of antithanatics in the 2060s, most humans are now functionally immortal barring accident and disease.

Finally, baseline humans are sexually dimorphic, with males (“men”) inseminating and females (“women”) developing the child inside the latter’s womb. (Many women use external wombs to save themselves the pains and labours of childbirth, however, and 1% of baseline humans are born with one of a variety of intersex conditions.) That said, most in the modern day would scoff at that simplistic description; surveys estimate that 5% of Earthlings and up to 80% of certain space habitats have had some kind of alteration to their sex, be it simple hormone therapy, full clean-room genetic replacement, or modification to the point that they cannot be said to fit cleanly into either category (herm­aph­ro­dit­ism is common in isolated settlements seeking maximum self-sustainability, and while rare, “exter­sex” gen­gi­neer­ing resulting in A Secret Third Thing is fashionable among bored Ouranian sybarites).

Society

Humans are a highly social animal, with a tendency to form complex societies while nobody is looking. They are coöperative and eager to help, particularly to those with whom they share some superficial commonality, and self-regulate their communities by organising into governments and voting on laws.

The most common setup for a human household is a chunk of an extended family; say, a grandfather, a mother and father, their cousin, and three kids. This is by no means universal or even global: on Mars, Selene, and northern regions of Earth, a household will be made up of a single group of two or three lovers who make a grand old fuss about the ritual of their children growing up and getting “their own place”. This trend goes even further on Mercury, where as a part of the rite of marriage, couples permanently neurally link their brains and become a joint legal person, acting thenceforth as one flowing mind that happens to be in control of two bodies. On Ceres, Io, and some ice giant moons, the base unit of a household is based more on friendship and occupation than a family connection; these worlds’ social structures originated in the kinship of asteroid miners and scientists sharing their barracks.

These households join together to form alkin larger settlements. The prototype on terrestrial worlds is the bustling organic city, where a web of open-air streets joins a central cluster of skyscrapers with lower-level row-houses on the outskirts, fading out into single houses in the country and empty protected areas. Elsewhere an arcology format is usual, where each house is just one cell of a closed, self-sustaining habitat: water returns to water, air returns to air, and human returns to humus.

The level of manual work undertaken in these societies, and its allocation, varies. Most countries on Earth — a conveniently average world, in contrast to its conservative reputation — are capitalist societies, where a citizen receives money in compensation to what people are willing to pay for their works. Being that most of the drudgery of life has long been automated away, rarely does someone strictly need to work for a living; the income from their work (often in the arts and entertainment, a prized talent among humans, or more boringly, management, curation of goods, and customer service) comes on top of a hefty universal income given to each citizen of their country. They then use this money to buy things. I’m sure you understand the idea.

Culture

Often humans are surprised to learn that their species is uncommon in its religiosity. Exceptions exist (the Church of the Luca looms large on Neptune, and lycans aren’t called man’s best friend for nothing), but the great majority of non-human biogens see the origin of the world as just not their problem and not something worth worrying about. For humans, it couldn’t be any different.

Being predisposed to curiosity, humans are wont to ponder the origins and ways of their world. One manifestation of this, the scientific method, gave them the physical means to go to space; the other, religion, gave them the spiritual fortitude. The largest sect are the monotheistic Abrahamic religions — Christianity, Judaism, Islam, Ve­ne­rean Mormonism, and the vernacular Chrislam — originating in the deserts of what is now the Con­fe­de­ra­tion. Sikhism is Martians’ primary faith, having been more resilient to their characteristic scepticism of any single human authority. Around Jupiter Toyn­bee­ism, holding that all dead will one day return to life anew around its rings, predominates, thanks to the group’s early settlement and the planet’s prominence in its holy texts (or, erm, film). Hinduism has been endlessly adapted to the local communities of all ten planets and countless moons, and a good many too practice vernacular varieties of paganism (“Mother Earth, Father Mars” adorns many a mantelpiece on the red planet).

Humans place a high value on the arts; while technogens are prolific and respected creators who can form whole immersive worlds in the blink of an eye, there is no set of words that will bring more joy to a human than “i made this”. (It’s not a hate thing — most of them have a neural link that makes them half technogen on their mum’s side anyway.) Storytelling is a time-honoured tradition; once thought of as a childish thing long superseded by books, the art took a central role in the off-world renaissance of the twenty-second century, an embrace of live, unaugmented, imperfect talent over the clean, perfect, but sterile æsthetics that had dominated the twenty-first. The art of performance bleeds over into music, another millennia-old craft and the species’ most adored skill, to the extent that the prospect of joining in with whalesong was what motivated the first merfolk, and vacuum-adapted spacers with no technical need for hearing have bone-conducting communicators regardless so they can whistle while they work.